John Adams - Fairfax/Alexandria,VA

I am looking for the spouse and parents of John Adams of Fairfax VA.John was born c1744 and died at the age of 100 in 1844 at his home in Alexandria, VA.It is possible that his wife was Elizabeth Thrift.John had a son James who married Sara "Sallie" Williams.I think John may have also had a daughter Nancy who married a Williams.Any information on this line would be greatly appreciated.